"""配置加载模块"""

import os
import secrets
from pathlib import Path

import yaml


class Config:
    """全局配置，从 config.yaml 加载"""

    def __init__(self, config_path: str = "config.yaml"):
        self.config_path = Path(config_path)
        self._data = {}
        if self.config_path.exists():
            with open(self.config_path, "r", encoding="utf-8") as f:
                self._data = yaml.safe_load(f) or {}

    def save(self):
        with open(self.config_path, "w", encoding="utf-8") as f:
            yaml.dump(self._data, f, allow_unicode=True, default_flow_style=False)

    def _resolve(self, p: str) -> Path:
        """将相对路径解析为配置文件所在目录的绝对路径"""
        path = Path(p)
        if not path.is_absolute():
            path = self.config_path.parent / path
        return path.resolve()

    # ── 路径 ──────────────────────────────────────────────

    @property
    def data_dir(self) -> Path:
        return self._resolve(self._get("paths.data_dir", "data"))

    @property
    def problems_dir(self) -> Path:
        return self._resolve(self._get("paths.problems_dir", "data/problems"))

    @property
    def papers_dir(self) -> Path:
        return self._resolve(self._get("paths.papers_dir", "data/papers"))

    @property
    def db_path(self) -> Path:
        return self._resolve(self._get("paths.db_path", "data/bank.db"))

    @property
    def backups_dir(self) -> Path:
        return self._resolve(self._get("paths.backups_dir", "data/backups"))

    @property
    def knowledge_tree_path(self) -> Path:
        return self._resolve(self._get("paths.knowledge_tree", "src/知识点树.md"))

    @property
    def knowledge_map_path(self) -> Path:
        return self._resolve(self._get("paths.knowledge_map", "src/knowledge_map.json"))

    # ── 服务端 ────────────────────────────────────────────

    @property
    def host(self) -> str:
        return self._get("server.host", "0.0.0.0")

    @property
    def port(self) -> int:
        return int(self._get("server.port", 8765))

    @property
    def token(self) -> str:
        t = self._get("server.token", "")
        if not t:
            t = secrets.token_hex(16)
            self._set("server.token", t)
            self.save()
        return t

    def regenerate_token(self) -> str:
        t = secrets.token_hex(16)
        self._set("server.token", t)
        self.save()
        return t

    # ── 默认值 ────────────────────────────────────────────

    @property
    def default_import_type(self) -> str:
        return self._get("defaults.import_type", "精选题")

    @property
    def max_backups(self) -> int:
        return int(self._get("defaults.max_backups", 30))

    # ── WebDAV ────────────────────────────────────────────

    @property
    def webdav_enabled(self) -> bool:
        return bool(self._get("webdav.enabled", False))

    @property
    def webdav_url(self) -> str:
        return self._get("webdav.url", "")

    @property
    def webdav_username(self) -> str:
        return self._get("webdav.username", "")

    @property
    def webdav_password(self) -> str:
        return self._get("webdav.password", "")

    @property
    def webdav_remote_path(self) -> str:
        return self._get("webdav.remote_path", "/tiku-backup")

    def set_webdav(self, url: str, username: str, password: str, remote_path: str = "/tiku-backup"):
        self._set("webdav.enabled", True)
        self._set("webdav.url", url)
        self._set("webdav.username", username)
        self._set("webdav.password", password)
        self._set("webdav.remote_path", remote_path)
        self.save()

    # ── helpers ───────────────────────────────────────────

    def _get(self, dotted_key: str, default=None):
        keys = dotted_key.split(".")
        val = self._data
        for k in keys:
            if isinstance(val, dict):
                val = val.get(k)
            else:
                return default
        return val if val is not None else default

    def _set(self, dotted_key: str, value):
        keys = dotted_key.split(".")
        d = self._data
        for k in keys[:-1]:
            if k not in d:
                d[k] = {}
            d = d[k]
        d[keys[-1]] = value


# 全局单例，通过 app 的 state 注入
_config_instance: Config | None = None


def get_config(config_path: str = "config.yaml") -> Config:
    global _config_instance
    if _config_instance is None:
        _config_instance = Config(config_path)
    return _config_instance


def set_config(cfg: Config):
    global _config_instance
    _config_instance = cfg